Tamper-resistant locking latch for casement windows

ABSTRACT

A locking latch assembly for a casement window has a handle block pivotally engaged on a base bracket which mounts on the jamb of the window. A cylinder lock is set in the block and can only be opened by a key. The bracket has slotted sidewalls which engage a cam at the inner end of the rotatable lock cylinder in the block. The cam and lock are enclosed and protected against tampering. The assembly has a replaceable handle.

United States Patent 2,339,980 1/1944 Cloutier Harold V. Taylor 40Parkway Circle, Scarsdale, N.Y. 10583 850,951

Aug. 18, 1969 July 20, 1971 Inventor Appl. No. Filed PatentedTAMPER-RESIST ANT LGCKING LATCH FOR CASEMENT WINDOWS 7 Claims, 14Drawing Figs.

[15. Cl 70/89, 70/137, 70/422, 292/108 Int. Cl. E051) 7/00, E05b 13/10,E050 3/04 Field of Search 70/89, 135,

References Cited UNITED STATES PATENTS 2,517,075 8/1950 Aquila 292/3532,542,332 2/1951 Holmsten 292/351 UX 2,987,908 6/1961 Pelcin H 70/208 X3,270,536 9/1966 Sprung 70/89 FOREIGN PATENTS 546,414 7/1956 Italy70/215 Primary Examiner-Albert G. Craig, Jr. Attorney-Po|achek &Saulsbury E ACT: A locking latch assembly for a casement window has ahandle block pivotally engaged on a base bracket which mounts on thejamb of the window. A cylinder lock is set in the block and can only beopened by a key. The bracket has slotted sidewalls which engage a cam atthe inner end of the rotatable lock cylinder in the block. The cam andlock are enclosed and protected against tampering. The assembly has areplaceable handle.

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Harold 1/. Ta l r AHORNEYS TAMPER-RESISTANT LOCKING LATCH FOR CASEMENTWINDOWS This invention concerns a device for latching and lockingcasement windows against opening by unauthorized persons. The device isintended to replace a conventional nonlocking type of casement windowlatch.

Heretofore, whereconventional nonlocking types of casement windowlatchesare .used,'it.is easy for a burglar or other unauthorized personto break out a portion of the glass pane of the easement window, and byreaching through the hole in the window, release the latch. and crank orotherwise work the window open. I

It has been proposed heretofore to provide a casementwindow with lockingmeans. Prior devices have been described in US. Pat. Nos. 2,2l4,884 and3,270,536. In US. Pat. No. 2,214,884 a lock is provided for a crankmechanism ,by means of which a casement window is opened and closedAprincipal disadvantage of this arrangement is that the lock is placed inan exposed position where it can be broken off by a hammer blow. Thelatch itself isnot held by any lock. In U.S.'Pat. No. 3,170,536 apush-type cylinder lock is attached to the base bracket of a casementwindow latch. The lock extends horizontally as a horizontal appendagewhere it can easily be broken off to release the handle of the-latch.This s of course objectionable.

The present invention is directed at overcoming the difficulties anddisadvantages of prior casement window protective devices by providing alocking type of casement window latch assembly which can easily beinstalled in place of a conventional nonlocking latcholn thepresentinvention a rotating cylinder-type lock is installed inside the handleportion of the latch where the lock is not exposed to tampering orbreaking off. The side of the latch facing toward the easement windowoccupies no more space than the nonlocking latch which it replaces. Thisavoids interference with inside'window screens. The device has a handleportion which is replaceable. This handle portion is made of softermetal than the hardened metal body of the device so that if tampering isattempted by prying or otherwise the handle portion will break offleaving the lock intact and the window almost impossible to open by thetamperer.

According to theinvention. the locking latch assembly includes a basebracket which is attached to the easement window jamb preferably bynonreversible screws. A handle block is pivotally attached to thebracket. A cylinder lock is disposed in the bodyof the block which hasan integral latching finger and carries a replaceable handle. The handleblock rotates on the axis-of its pivot pin and swings the latchingfinger to a position behind a fixed catch on the striker plate of theeasement window to hold the window closed. Opening of the window on itshinges is accomplished by reverse rotation of handle block. Locking isaccomplished by rotating the cylinder lock in the block by a suitablekey. The lock cylinder has a cam at its inner end engaging slots insides of the base bracket. Upon removal-of the key the block is left inlocked condition to prevent rotation of the block and unauthorizedopening of the window. The lock and locking earn are so encased in thehandle block that they cannot be reached for imposing such damage aswill'be effective to open'the latch. The device is arrangedf'so that theclosed latch covers and conceals at least one of the screws holding themounting bracket so that this bracket'cannot be pried loose. If pryingof the locked assembly by use of a prying tool is attempted, thereplaceable handle will break off first before any damage can be down tothe locking parts.

The assembled device is flat on one side to permit installation of thedevice in place of a standard, conventional, flatsided nonlocking latch.The fiat side facing the window permits conventional interior windowscreens to be installed withoutinterference by the locking latch. -Thedevice will be manufactured in left-hand and right-hand formsforinstallation on left-opening and right-opening casement windows.

For further comprehension reference may be had to the following detaileddescription taken in connection'with the accompanying drawing, in whichFIG. 1 is a side view ofthe locking latch assembly embodyingtheinvention shown'installed on a casement window jamb. The jamb isshown in vertical section and the latch assembly is shown in open,unlocked position.

FIG. 2 is an edgewise bottom plan view taken on line 2-2 of FIG. 1,showing the open latch assembly, the" window jamb being omitted.

FIG. 3 is a front or inside elevational view of the latch assembly shownin closed position jamb of a casement window.

FIG. 4 is a vertical sectional view taken on line4-4 of FIG. 3 showinginternal construction of the latch assembly, the windowjamb beingomitted.

FIG. 5 and FIG. 6 are opposite side views of the latch as-,

' sembly taken on lines 5-5 and 6-6 respectively of FIG. 4, the I windowjamb being shown in vertical section, with parts of the window catchbeing omitted from FIG. 6.

FIG. 7 is an edgewise elevational view of the latch assembly shown inclosed position, taken on 7-7 of FIG. 6, the window jamb and basebracket being omitted.

FIG. 8 is an edgewise view of the handle block latch assembly.-

FIGS. 9 and 10 are opposite side views of the handle block taken onlines 9-9 and 10-10 respectively of FIG. 8.

FIGS. 11 and 12 are cross-sectional views taken on lines 11-11 and 12-12respectively through the block as sown in FIG. 9. 1

FIG. 13 is a side view of the base bracket per se of the latch assembly.

FIG. 14 is a plan view taken on line 14-of FIG. 13.

Referring first to FIGS. 1-7, there is shown the locking 'latch assemblyembodying the invention. The latch assembly includes a generallyrectangular, massive block 20 made of steel, bronze or other very tough,strong metal. Block 20 is shown alone in FIGS. 8-12. The block is formedwith an integral flat, arcuate finger 22 extending rearwardly of theblock. A deep groove 24 with slanted bottom is formed in the per se ofthe 'block lengthwise thereof alongside of finger 22. Part of sidewall26 of the block is cut away to define a recess 28 at the other ,side offinger 22. The finger 22 extends upwardly .beyond end 27 of the block.Near the other end 29 of the block is a lateral, enlargement 30 in whichis a cylindrical bore 32. Opposite ends 33, 34of the bore are formedwith annular enlargements. Groove 24 extends up to bore end 33; see'FIG.

8. Aligned holes 35, 36 are formed in sidewall 38 and in inner wall 39of which finger 22 is an extension.

The latch assembly further includes a cylinder. lock 40. This lock has acylindrical casing 42 nonrotatably seated in bore 32 with annular flange41-engaged at bore end 33; see "FIG. 4. Cylinder 44 of the lock has akeyhole 45 at its exposed flanged end-43. The cylinder extends axiallythrough casing 42 and is rotatable therein. The cylinder terminates atthe inner end of the casing inside bore end 34. An eccentric cam 50 isengaged on 'noncircular stub shaft 52 extending axially beyond thecylinder. On this shaft is engaged a screw 54 which holds the cam sothat the cam rotates with the cylinder when a suitable key (notshown) isinserted in the keyhole and .rotated( The cam-has adjacent edge portions50a and 50b which are radially shorter than the remaining circularportion 500 of the cam; see FIGS. 2 and 7. A space 55 is defined betweeninner end 56 of wall 39 of the block and adjacent cutaway portion 58 ofend 33 of the bore. The inner end 56 of wall 39 is cylindrically curved.

An L-shaped handle 57 is replaceably secured .by screws 59 to end 29 ofthe block. The handle is made of a material less strong than that of theblock so that application of a prying tool to the handle in an attemptto open the latch will result in breaking off of the handle before theblock or lock can be damaged.

The latch assembly also includes a base bracket 60 shown in FIGS. 1-6,13 and 14. This bracket is an elongated member with flat, rectangularbackwall '62 formed with holes 63 near opposite ends to receive screws64. 65 for mounting the bracket "on amb 69. Two tapered flat sidewallsor flanges 66, 68 extend perpendicularly to wall 62 at opposite edgesthereof, Wall 66 has a short slot 70 formed In its narrow end edge. Wall68 is slightly longer than wall 66 and has a shallow slot 74 formed inits inside face just beyond the edge of wall 66. A long rectangularopening 76 is formed in wall 62 through which curved finger 22 of thelatch extends in the both open and closed positions of the latch. Finger22 extends through the space between the walls 66. 68. Aligned holes 78are formed in walls 66, 68. A pivot pin 80 extends through holes 78 aswell as holes 35, 36 in the walls of the block. Open position is shownin FIG. 1 and the closed position is shown in FIGS.,36.

Finger 22 extends through hole 81 in jamb 69 and engages on catch 82extending laterally of striker plate 84 mounted by screws 86 on casementwindow sash 88. Bracket 60 is mounted on the stationary jamb 69 of thecasement window;

The plane of finger 22 is perpendicular to that of jamb 69. Window pane92 is mounted in sash 88 which can swing outwardly away from the jamb asindicated by arrow A in FIG. 1, when the latch block is in open positionwith finger 22 disengaged from catch 82.

Installation of the latch assembly is easily accomplished by securingscrews 64, 65 in holes 94 in the jamb. In the closed position of thelatch assembly lower screw 64 is covered byblock 20 as shown in FIGS. 5.6. If an intruder attempts to remove the latch assembly by prying offbracket 60 he may break off the head of screw 65 but he cannot gainaccess to the covered and protected screw 64.

The window is shown closed in FIG. I, but the latch assembly is open andlock 40 is unlocked. To close the latch it is rotated on pin 80 as anaxis until finger 22 engages catch 82 as shown in FIG. 5. To lock thelatch assembly a key will be insertedin keyhole 45 and cylinder 44 willbe turned. This will turn cam 50-t'rom the position where edge portions50a, 50b are clear of slots 70 and 74 in bracket walls 66, 68 to theposition where-circular edge portion 50c engages in both slots 70 and74. For clarity this closed position of the cam is shown without thebracket in FIG. 7. It will be noted the circular edge portion 50c thenextends laterally at the left into space 55 and also up to end edge 56of wall 39. The cam 50 is sown in dotted lines of FIGS. and 6 engagedwith the sidewalls of the bracket. The only way the latch assembly canproperly be unlocked is by means of a suitable key inserted in lock 40.

The construction described is such that the locked latch assembly willeffectively resist destructive prying and hammering in an unauthorizedattempt to open it. The latch assembly readily replaces conventionalnonlocking casement window latches. It provides maximum security in thefollowing ways among others:

I. The lock and locking cam are enclosed and encased in v the massivehandle block 22.

-2. One mounting screw of the base'bracket remains covered by the blockin its closed lock so that the bracket cannot be pried 05.

3. The space 100 between the closed block and bracket as shown in FIGS.5 and 6 is so narrow that no effective prying tool can be inserted. Thelower edges of the block are also rounded to make more difficult anyattempt at prying the block open.

4. The replaceable handle 57 which should be made of softer metal thanblock 20 will break off if a prying force is applied to it before anybreakage or damage can occur to other parts of the assembly.

The device can be manufactured at relatively low cost. It will providelong, useful. trouble-free service. No special tools or special skillsare required for installation.

Whatlclaim is: i

I. A locking latch assembly for a hinged casement window having a sashswinging open outwardly and closing against a stationary 'amb, said sashhaving a striker plate and catch mounted t ereon, said assemblycomprising anelongated bracket having a flat backwall mountable on thejamb, said wall having a long opening therein, said bracket having apair of spaced slotted sidewalls extending perpendicularly to saidbackwall; a generally rectangular, massive block pivotally mounted nearone end thereof on said sidewalls; said block being rotatable betweenopen and'closed positions with respect to said bracket, said blockhaving an outwardly ex'- tending finger for engaging said catch, saidfinger extending between said sidewalls and through the opening in thebackwall, said block further having a cylindrical bore formed thereinnear the other end thereof; a key-operated lock with rotatable cylinderengaged in said bore; and an eccentric cam at one end of the cylinderinside the bore arranged to engage in slots in said sidewalls of thebracket to lock the block against pivotal rotation and disengagement ofsaid finger from said catch, said backwall of the bracket has holes nearopposite ends for-receiving screws to mount the bracket on said jamb,said holes being so located that at least one of the screws is coveredby the block when in closed position to prevent access by a tool to thecovered screw, a handle mounted at said other end of the block forturning the block when the lock is opened to disengage said cam from thesidewalls of the bracket, said block is formed with a longitudinalgroove an recess to receive said sidewalls respectively of the bracketto enable said cam to engage the slots in said sidewalls when the blockis in closed position.

2. A locking latch assembly as defined in claim 1, wherein the handle isreplaceably mounted.

3. A locking latch assembly as defined in claim 2 wherein said handle ismade of a material less strong than that of the block to break beforedamage can be done to the lock and block by a prying force applied tothe handle in an attempt to open the latch.

4. A locking latchassembly as defined in claim 1 wherein said boreextends between opposite faces of said block, and a pivot pin rotatablymounted the block to the bracket, said pin being located close to oneface of the block so that said face is close to the backwall of thebracket in the closed position of the block to prevent insertion of aprying tool between the block and bracket.

5. A locking latch assembly as defined in claim 4 wherein the other endof the cylinder has a keyhole for receiving said key, said keyhole beingexposed at the other face of the block.

6. A locking latch assembly as defined in claim 5, wherein said bore hasend portions of larger diameter than an intermediate portion of the boresaid lock comprising a cylindrical casing seated in the bore and havingan end flange engaged in one of said end portions of the bore, said cambeing rotatably disposed in the other end portion of the bore, saidcylinder being rotatably disposed in said casing, whereby said flangeand said cam retain the lock in the block.

7. A locking latch assembly as defined in claim 6, wherein said handleis replaceably mounted and is made of a material less strong than thatof the block to break before damage can be done to the lock and block bya prying force applied to the handle in an attempt to open the latch.

1. A locking latch assembly for a hinged casement window having a sashswinging open outwardly and closing against a stationary jamb, said sashhaving a striker plate and catch mounted thereon, said assemblycomprising an elongated bracket having a flat backwall mountable on thejamb, said wall having a long opening therein, said bracket having apair of spaced slotted sidewalls extending perpendicularly to saidbackwall; a generally rectangular, massive block pivotally mounted nearone end thereof on said sidewalls, said block being rotatable betweenopen and closed positions with respect to said bracket, said blockhaving an outwardly extending finger for engaging said catch, saidfinger extending between said sidewalls and through the opening in thebackwall, said block further having a cylindrical bore formed thereinnear the other end thereof; a key-operated lock with rotatable cylinderengaged in said bore; and an eccentric cam at one end of the cylinderinside the bore arranged to engage in slots in said sidewalls of thebracket to lock the block against pivotal rotation and disengagement ofsaid finger from said catch, said backwall of the bracket has holes nearopposite ends for receiving screws to mount the bracket on said jamb,said holes being so located that at least one of the screws is coveredby the block when in closed position to prevent access by a tool to thecovered screw, a handle mounted at said other end of the block forturning the block when the lock is opened to disengage said cam from thesidewalls of the bracket, said block is formed with a longitudinalgroove an recess to receive said sidewalls respectively of the bracketto enable said cam to engage the slots in said sidewalls when the blockis in closed position.
 2. A locking latch assembly as defined in claim1, wherein the handle is replaceably mounted.
 3. A locking latchassembly as defined in claim 2 wherein said handle is made of a materialless strong than that of the block to break before damage can be done tothe lock and block by a prying force applied to the handle in an attemptto open the latch.
 4. A locking latch assembly as defined in claim 1wherein said bore extends between opposite faces of said block, and apivot pin rotatably mounted the block to the bracket, said pin beinglocated close to one face of the block so that said face is close to thebackwall of the bracket in the closed position of the block to preventinsertion of a prying tool between the block and bracket.
 5. A lockinglatch assembly as defined in claim 4 wherein the other end of thecylinder has a keyhole for receiving said key, said keyhole beingexposed at the other face of the block.
 6. A locking latch assembly asdefined in claim 5, wherein said bore has end portions of largerdiameter than an intermediate portion of the bore said lock comprising acylindrical casing seated in the bore and having an end flange engagedin one of said end portions of the bore, said cam being rotatablydisposed in the other end portion of the bore, said cylinder beingrotatably disposed in said casing, whereby said flange and said camretain the lock in the block.
 7. A locking latch assembly as defined inclaim 6, wherein said handle is replaceably mounted and is made of amaterial less strong than that of the block to break before damage canbe done to the lock and block by a prying force applied to the handle inan attempt to open the latch.